The broad objective of this research is to derive indices of neurophysiological activity that would contribute to our understanding of the neural mechanisms underlying learning disabilities. The specific aim of this project is to establish reliable EEG measures of the degree and types of childhood learning disability in order to more rigorously quantify as well as provide support for the learning disability taxonomy used to classify children. The hypothesis that learning disability subtypes can be differentiated by the measurement of multiple channel, EEG spectral coherence was formulated following a pilot study conducted in our laboratory which indicated that interhemispheric EEG spectral coherence at frequencies above 20 Hz was consistently lower in the disabled learner than in the normal control. In this project we plan to obtain spectral coherence measures from EEG's collected during information processing by children representing specific subtypes of learning disabilities and normal controls as a basis for testing and extending this hypothesis to additional subtypes. The populations to be tested in the experimental design include learning disabled children (age 10-12), divided according to the type of academic problem, representing children with primary difficulties in arithmetic (N=30), reading (N=30), and both reading and arithmetic (N=30) along with normal controls (N=30).